1. Field of the Invention
The present invention relates to a blue luminescent polymer and an organoelectroluminescent device using the same, and more particularly, to a blue luminescent polymer containing an indeno (or indolo) carbazole unit in its main polyarylene chain and an organoelectroluminescent device using the same, thus having high emission efficiency and high color purity.
2. Description of the Related Art
Organic electroluminescent devices (organic EL devices) are active emission display devices. When a current is provided to fluorescent or phosphor organic compounds thin films (organic films), electrons and holes are combined in the organic films, thus emitting light. Organic EL devices have many advantages, such as being lightweight, a simplified manufacturing process, high resolution, and wide viewing angles. Further, the organic EL devices can completely realize a moving picture with excellent color purity and low power consumption. Therefore, such organic EL devices are suitable for portable electrics.
Organic EL devices are classified into low molecular weight organic EL devices and polymer EL devices according to a material for forming an organic film.
In low molecular weight organic EL devices, organic films are formed by vacuum deposition. Low molecular weight organic EL devices have many advantages. For example, emission materials for the low molecular weight organic EL devices can be easily refined to achieve high purity, and color pixels can be easily formed. However, such devices have problems, such as low quantum efficiency, crystallization of thin films, and low color purity.
Meanwhile, in polymer organic EL devices, organic films can be formed by spin coating or printing. The use of spin coating and printing simplifies the manufacturing process, and lowers manufacturing costs. In addition, such organic films have excellent mechanical characteristics.
However, polymer organic EL devices also have many disadvantages including low color purity, high operating voltage, low efficiency, and the like. As a result, much research into the polymer organic EL devices has been conducted to overcome these disadvantages. For example, polymers containing fluorene are copolymerized (U.S. Pat. No. 6,169,163 and Synthetic Metal, Vol. 106, pp. 115-119, 1999), or blended (Applied Physics Letter, Vol. 76, No. 14, pp. 1810, 2000) to improve electroluminescent characteristics. However, the current improvement of electroluminescent characteristics is far from a desirable level.